In power semiconductor devices, for examples IGFETs (insulated gate field effect transistors) a load current typically flows in a vertical direction between two load electrodes formed at opposite sides of a semiconductor die. In a blocking mode field plate structures extending from one side into the semiconductor die deplete a drift portion of the semiconductor die and facilitate higher dopant concentrations in the drift portion, wherein the on state resistance can be decreased without adverse impact on the blocking capability. Shrinking the field plate structures as well as gate structures increases an active transistor area.
It is desirable to improve the switching characteristics of semiconductor devices including transistor cells and field plate structures.